Sense of coherence (SOC) scale measures one’s orientation to life. SOC is the core construct in Antonovsky's salutogenic model of health. It has been shown that weak SOC correlates with poor perceived health, low quality of life, and increased mortality. Some studies have indicated that SOC is not stable across life, but there are no previous studies on how a change of SOC is reflected in mortality. However, there is some evidence that a change in perceived quality of life is associated with mortality. The study explores the association between the change in SOC and mortality using longitudinal data from a cohort of middle-aged Finnish men recruited between 1986 and 1989. Approximately 11 years after the baseline examinations, between 1998 and 2001, 854 men returned the SOC questionnaire a second time. The baseline SOC was adjusted for the regression to the mean phenomenon between the two measurements. The hazard ratios of the SOC difference scores were adjusted for initial SOC age and 12 somatic risk factors of mortality (alcohol consumption, blood pressure, body mass index, cholesterol concentration, physical activity, education, smoking, marital status, employment status, history of cancer, history of cardiovascular disease and diabetes). SOC was not stable among middle-aged Finnish men and a decline in SOC was associated with an increased hazard of all-cause mortality. In the fully adjusted model, a decrease of one standard deviation (SD) of the SOC mean difference increased the mortality hazard by about 35 %, two SDs decrease about 70 %, and 2.5 SDs about 100 %. Strengthening SOC showed a limited association with decreasing mortality hazards in the age-adjusted model. Policies, strategies, or plans, supporting SOC in the middle-age may help to decrease mortality and increase quality of life in later years.